13
votes
Accepted
Loudness unit, as logarithm of mean squared?
Short Answer: Using the mean of the square (or the square of the RMS) represents the energy in the acoustical signal.
Longer Answer:
Sound waves that you hear are made of vibrations in the air. There ...
8
votes
Difference Between Particle Velocity and Wave Velocity in a Longitudinal Wave
It might seem intuitive to assume that the particle velocity should be identical to the wave velocity
No, particle velocity and wave velocity are different things.
Look at the longitudinal wave in ...
6
votes
Difference Between Particle Velocity and Wave Velocity in a Longitudinal Wave
Yes, there is a difference between particle velocity ($v_p$) and wave velocity ($v$) in a longitudinal wave.
The wave velocity is the speed at which wavefronts propagate, calculated as $v = \lambda f$,...
4
votes
Difference Between Particle Velocity and Wave Velocity in a Longitudinal Wave
This wave is a disturbance of a medium that travels steadily onward.
A given time, some particle is being disturbed. It moves back and forth. This is particle velocity.
Wave velocity is about how long ...
2
votes
Accepted
Why and how white noise cancels other background noises?
Introduction
First of all, let me state that the clip you provided does not contain white noise, but some kind of filtered noise. I haven’t analysed it to conclude on the “colour” of the noise but it ...
2
votes
Why does air vibration produce a spherical wavefront and not a plane wavefront?
Assuming that the question is related to sound waves in air, then when an object sets air into vibration, it sends out sound waves in all directions away from the point of vibration.
This creates ...
1
vote
Loudness unit, as logarithm of mean squared?
Michael's answer is fantastic, but since someone might find this through specifically searching for loudness units, I thought it worth writing an additional answer more specific to the LUFS unit.
As ...
1
vote
How can I determine sound speed of ions in plasma sheath
The formal definition for the speed of sound is given as:
$$
C_{s}^{2} = \frac{ \partial P }{ \partial \rho } \tag{0}
$$
where $P$ is the total thermal pressure and $\rho$ is the total mass density. ...
1
vote
Do wavenumber pairs exist for standing waves?
I'm just going to focus on the spatial Fourier transform / spatial dependence in this answer, so the answer can be written in terms of properties of the Fourier transform; calculating the time ...
1
vote
How to justify sound propagation is a linear time-invariant (LTI) system?
Sound waves are not linear, but since we rarely have shock waves indoors, we can usually approximate the sound wave equation as linear for room acoustics.
While simple boundary conditions will, in ...
1
vote
Mysterious sound from measurement setup in "zero measurement"
If your anechoic chamber had ventilation provided by the HVAC system in your building, the most likely cause was fan noise coming in through the vent ducts. Since the motors that run the fan operate ...
1
vote
Why does air vibration produce a spherical wavefront and not a plane wavefront?
Introduction
The assumption that the vibration of objects (the shape of the resulting wavefront is not dependent only on the material but other factors too) produces spherically expanding waves is ...
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